Chains
are usually made in one of two styles, according to their intended use:

Those
designed for lifting, such as when used with a hoist, or for securing,
such as with a bicycle lock, have
links that are torus shaped, which makes the chain flexible in two
dimensions.

Those
designed for transferring power in machines have links designed to
mesh with the teeth of the sprockets of the machine, and are flexible
in only one dimension. They are known as Roller chains, typically used
with anchors, rope
and a windlass.

SolarNavigator
began life in 1990s as an attempt to prove that the world could be
navigated on solar power alone in a SWATH
boat. Since then the hull design has been refined to a SWASSH
configuration - and electronics have developed to the stage where this
vessel could be the first true fully autonomous Robot Ship - ideal for
extended 365 day a year hydrographic surveying
and other persistent ocean monitoring and surveillance.